A monitoring toolkit for banksia woodlands: comparison of different scale methods to measure recovery of vegetation after fire

Mark Brundrett, Ricky van Dongen, Bart Huntley, Natasha Tay, Vanda Longman

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Here, we compare the efficiency and accuracy of remote sensing and plot-based methods for measuring vegetation cover for the understory and canopy of banksia woodland in an urban area of Western Australia. Methods compared were visual estimation, foliage cover computation from photographs, satellite imagery and aerial photographs. Observations and images from 1 m 2 , 100 m 2 and 625 m 2 quadrats measured cover of small plants, understory plants and trees respectively. Aerial photography and satellite imagery allowed the number, height and cover of trees to be estimated in 625 m 2 and 1 ha plots. The accuracy of methods was compared using a 28 month time series commencing before and after an intense bushfire that removed all foliage cover. Directly comparable methods were in close agreement and in combination allowed plant recovery to be quantified in great detail. Visual estimation of cover in the field was time-consuming but necessary to measure the contribution of individual species. Visual estimates from 1 m 2 downward photos allowed functional groups of plants to be measured. The number of green pixels selected manually in photographs confirmed that cover calculated from ground-based photographs using algorithms was accurate, except when cover was very low. We developed a new algorithm for computing cover from photographs that was accurate at low cover (Gperc). Canopy cover estimation by algorithm from upward photographs was subject to more errors, requiring exclusion of some images. Landsat satellite images allowed the impacts of severe drought and previous fires to be identified against a background of relatively consistent seasonal variations since 1988. Aerial photographs from 1953 onwards showed gradual recolonisation by banksia woodland trees over 60 years following tree felling. These methods provide a toolkit for monitoring vegetation recovery after disturbance and baseline data for monitoring banksia woodland. This toolkit should also be suitable for most other plant communities.

Original languageEnglish
Pages (from-to)33-54
Number of pages22
JournalRemote Sensing in Ecology and Conservation
Volume5
Issue number1
DOIs
Publication statusPublished - 1 Mar 2019

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Banksia
photographs
photograph
woodlands
woodland
Fires
Recovery
vegetation
Satellite imagery
Monitoring
monitoring
aerial photograph
satellite imagery
foliage
understory
Antennas
Aerial photography
canopy
Drought
methodology

Cite this

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title = "A monitoring toolkit for banksia woodlands: comparison of different scale methods to measure recovery of vegetation after fire",
abstract = "Here, we compare the efficiency and accuracy of remote sensing and plot-based methods for measuring vegetation cover for the understory and canopy of banksia woodland in an urban area of Western Australia. Methods compared were visual estimation, foliage cover computation from photographs, satellite imagery and aerial photographs. Observations and images from 1 m 2 , 100 m 2 and 625 m 2 quadrats measured cover of small plants, understory plants and trees respectively. Aerial photography and satellite imagery allowed the number, height and cover of trees to be estimated in 625 m 2 and 1 ha plots. The accuracy of methods was compared using a 28 month time series commencing before and after an intense bushfire that removed all foliage cover. Directly comparable methods were in close agreement and in combination allowed plant recovery to be quantified in great detail. Visual estimation of cover in the field was time-consuming but necessary to measure the contribution of individual species. Visual estimates from 1 m 2 downward photos allowed functional groups of plants to be measured. The number of green pixels selected manually in photographs confirmed that cover calculated from ground-based photographs using algorithms was accurate, except when cover was very low. We developed a new algorithm for computing cover from photographs that was accurate at low cover (Gperc). Canopy cover estimation by algorithm from upward photographs was subject to more errors, requiring exclusion of some images. Landsat satellite images allowed the impacts of severe drought and previous fires to be identified against a background of relatively consistent seasonal variations since 1988. Aerial photographs from 1953 onwards showed gradual recolonisation by banksia woodland trees over 60 years following tree felling. These methods provide a toolkit for monitoring vegetation recovery after disturbance and baseline data for monitoring banksia woodland. This toolkit should also be suitable for most other plant communities.",
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A monitoring toolkit for banksia woodlands : comparison of different scale methods to measure recovery of vegetation after fire. / Brundrett, Mark; van Dongen, Ricky; Huntley, Bart; Tay, Natasha; Longman, Vanda.

In: Remote Sensing in Ecology and Conservation, Vol. 5, No. 1, 01.03.2019, p. 33-54.

Research output: Contribution to journalArticle

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T2 - comparison of different scale methods to measure recovery of vegetation after fire

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AU - van Dongen, Ricky

AU - Huntley, Bart

AU - Tay, Natasha

AU - Longman, Vanda

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